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GPU/HW: Minor improvements to texture filtering

This commit is contained in:
Connor McLaughlin 2020-04-23 15:08:28 +10:00
parent 13e2b28f50
commit 30033ed4aa
1 changed files with 18 additions and 16 deletions
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34
src/core/gpu_hw_shadergen.cpp
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@ -573,27 +573,29 @@ float4 SampleFromVRAM(int4 texpage, int2 icoord)
#if TEXTURED
#if TEXTURE_FILTERING
int2 icoord = int2(v_tex0);
float2 pcoord = frac(v_tex0) - float2(0.5, 0.5);
float2 poffs = sign(pcoord);
pcoord = abs(pcoord);
// Compute the coordinates of the four texels we will be interpolating between.
// TODO: Find some way to clamp this to the triangle texture coordinates?
float2 texel_top_left = frac(v_tex0) - float2(0.5, 0.5);
float2 texel_offset = sign(texel_top_left);
float4 fcoords = v_tex0.xyxy + float4(0.0, 0.0, texel_offset.x, texel_offset.y);
// TODO: Clamp to page
float4 tl = SampleFromVRAM(v_texpage, int2(v_tex0));
float4 tr = SampleFromVRAM(v_texpage, int2(min(v_tex0.x + poffs.x, 255.0), v_tex0.y));
float4 bl = SampleFromVRAM(v_texpage, int2(v_tex0.x, min(v_tex0.y + poffs.y, 255.0)));
float4 br = SampleFromVRAM(v_texpage, int2(min(v_tex0.x + poffs.x, 255.0), min(v_tex0.y + poffs.y, 255.0)));
// Load four texels.
float4 s00 = SampleFromVRAM(v_texpage, int2(fcoords.xy));
float4 s10 = SampleFromVRAM(v_texpage, int2(fcoords.zy));
float4 s01 = SampleFromVRAM(v_texpage, int2(fcoords.xw));
float4 s11 = SampleFromVRAM(v_texpage, int2(fcoords.zw));
// Compute alpha from how many texels aren't pixel color 0000h.
float tl_a = float(VECTOR_NEQ(tl, TRANSPARENT_PIXEL_COLOR));
float tr_a = float(VECTOR_NEQ(tr, TRANSPARENT_PIXEL_COLOR));
float bl_a = float(VECTOR_NEQ(bl, TRANSPARENT_PIXEL_COLOR));
float br_a = float(VECTOR_NEQ(br, TRANSPARENT_PIXEL_COLOR));
float a00 = float(VECTOR_NEQ(s00, TRANSPARENT_PIXEL_COLOR));
float a10 = float(VECTOR_NEQ(s10, TRANSPARENT_PIXEL_COLOR));
float a01 = float(VECTOR_NEQ(s01, TRANSPARENT_PIXEL_COLOR));
float a11 = float(VECTOR_NEQ(s11, TRANSPARENT_PIXEL_COLOR));
// Bilinearly interpolate.
float4 texcol = lerp(lerp(tl, tr, pcoord.x), lerp(bl, br, pcoord.x), pcoord.y);
ialpha = lerp(lerp(tl_a, tr_a, pcoord.x), lerp(bl_a, br_a, pcoord.x), pcoord.y);
if (ialpha == 0.0)
float2 weights = abs(texel_top_left);
float4 texcol = lerp(lerp(s00, s10, weights.x), lerp(s01, s11, weights.x), weights.y);
ialpha = lerp(lerp(a00, a10, weights.x), lerp(a01, a11, weights.x), weights.y);
if (ialpha < 0.5)
discard;
texcol.rgb /= float3(ialpha, ialpha, ialpha);